随着新能源汽车的发展,可充电的能循环使用的高能量密度电池迎来了巨大的发展契机,由于Li离子电池的超高能量密度,稳定的循环性能,引发了人们广泛的关注与研究,Li-CO_2电池作为一种新型的Li离子电池,由于节能减排以及温室效应的影响下,...随着新能源汽车的发展,可充电的能循环使用的高能量密度电池迎来了巨大的发展契机,由于Li离子电池的超高能量密度,稳定的循环性能,引发了人们广泛的关注与研究,Li-CO_2电池作为一种新型的Li离子电池,由于节能减排以及温室效应的影响下,也渐渐成为了研究热点。目前,对于Li-CO_2电池的研究,主要集中在正极电极材料上,经历了KB到纳米碳材料的过程,如今使用石墨烯作为正极材料,放电比容量已经达到14722 m Ag^(-1),并达到了超过20个周期的循环周期,已初具使用价值,具备极大的研究潜力和前景。展开更多
Thermodynamics of the precipitation from Li-Fe（II）-P-H2O system at 298 K was investigated.The results demonstrate that LiFePO4 can be formed at room temperature under pH value of 0-11.3,and the impurities Li3PO4 and...Thermodynamics of the precipitation from Li-Fe（II）-P-H2O system at 298 K was investigated.The results demonstrate that LiFePO4 can be formed at room temperature under pH value of 0-11.3,and the impurities Li3PO4 and Fe（OH）2 will be yielded at pH value above 11.3 and 12.9,respectively.The optimum pH value for LiFePO4 precipitation is 8-10.5.Considering the low rate of phase transformation kinetics,metastable Li-Fe（II）-P-H2O system was also studied.The results indicate that equimolar ratio of co-precipitation precursor Fe3（PO4）2.8H2O and Li3PO4 cannot be obtained at the initial molar ratio 1：1：1 and 1：1：3 of Li：Fe：P.In contrast,equimolar ratio of the co-precipitation precursor can be yielded by adjusting the pH value to 7-9.2,matching the molar ratio 3：1：1 of Li：Fe：P,meaning that Li＋-excess is one of the essential conditions for LiFePO4 preparation by co-precipitation method.展开更多
The layered Li[Ni1/3Mn1/3Co1/3]O2 was separately synthesized by pretreatment process of ball mill method and solution phase route, using [Ni1/3Co1/3Mn1/3]3O4 and lithium hydroxide as raw materials. The physical and el...The layered Li[Ni1/3Mn1/3Co1/3]O2 was separately synthesized by pretreatment process of ball mill method and solution phase route, using [Ni1/3Co1/3Mn1/3]3O4 and lithium hydroxide as raw materials. The physical and electrochemical behaviors of Li[Ni1/3Mn1/3Co1/3]O2 were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, field emission scanning electron microscopy （FESEM） and electrochemical charge/discharge cycling tests. The results show that the difference in pretreatment process results in the difference in compound Li[Ni1/3Co1/3Mn1/3]O2 structure, morphology and the electrochemical characteristics. The Li[Ni1/3Mn1/3Co1/3]O2 prepared by solution phase route maintains the uniform spherical morphology of the [Ni1/3Co1/3Mn1/3]3O4, and it exhibits a higher capacity retention and better rate capability than that prepared by ball mill method. The initial discharge capacity of this sample reaches 178 mA-h/g and the capacity retention after 50 cycles is 98.7% at a current density of 20 mA/g. Moreover, it delivers high discharge capacity of 135 mA-h/g at a current density of 1 000 mA/g.展开更多
Different LiNi0.8Co0.15Al0.05O2 cathode materials were washed by ethanol solvent. Inductively coupled plasma atomic emission spectroscopy（ICP-AES）, Fourier transformed infrared（FTIR） spectrum, X-ray diffraction（...Different LiNi0.8Co0.15Al0.05O2 cathode materials were washed by ethanol solvent. Inductively coupled plasma atomic emission spectroscopy（ICP-AES）, Fourier transformed infrared（FTIR） spectrum, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, charge-discharge test and electrochemical impedance spectroscopy（EIS） were used to evaluate the elemental contents, structures, morphologies and electrochemical properties of samples. The results show that ethanol washing can remove effectively the synthetic residues LiOH/Li2 O on the freshly-prepared LiNi0.8Co0.15Al0.05O2 and make the sample much more resistant to H2O and CO2, without destroying its bulk structure, surface morphology and electrochemical performances. Moreover, the discharge specific capacity and cycle performance of LiNi0.8Co0.15Al0.05O2 after storage in air with a relative humidity of 80% for three months are improved by immediate ethanol washing.展开更多
文摘随着新能源汽车的发展,可充电的能循环使用的高能量密度电池迎来了巨大的发展契机,由于Li离子电池的超高能量密度,稳定的循环性能,引发了人们广泛的关注与研究,Li-CO_2电池作为一种新型的Li离子电池,由于节能减排以及温室效应的影响下,也渐渐成为了研究热点。目前,对于Li-CO_2电池的研究,主要集中在正极电极材料上,经历了KB到纳米碳材料的过程,如今使用石墨烯作为正极材料,放电比容量已经达到14722 m Ag^(-1),并达到了超过20个周期的循环周期,已初具使用价值,具备极大的研究潜力和前景。
基金Project (2007CB613603) supported by the National Basic Research Program of China
文摘Thermodynamics of the precipitation from Li-Fe（II）-P-H2O system at 298 K was investigated.The results demonstrate that LiFePO4 can be formed at room temperature under pH value of 0-11.3,and the impurities Li3PO4 and Fe（OH）2 will be yielded at pH value above 11.3 and 12.9,respectively.The optimum pH value for LiFePO4 precipitation is 8-10.5.Considering the low rate of phase transformation kinetics,metastable Li-Fe（II）-P-H2O system was also studied.The results indicate that equimolar ratio of co-precipitation precursor Fe3（PO4）2.8H2O and Li3PO4 cannot be obtained at the initial molar ratio 1：1：1 and 1：1：3 of Li：Fe：P.In contrast,equimolar ratio of the co-precipitation precursor can be yielded by adjusting the pH value to 7-9.2,matching the molar ratio 3：1：1 of Li：Fe：P,meaning that Li＋-excess is one of the essential conditions for LiFePO4 preparation by co-precipitation method.
基金Project(20871101)supported by the National Natural Science Foundation of ChinaProject(2009WK2007)supported by Key Project of Science and Technology Department of Hunan Province,ChinaProject(CX2009B133)supported by Colleges and Universities in Hunan Province Plans to Graduate Research and Innovation,China
文摘The layered Li[Ni1/3Mn1/3Co1/3]O2 was separately synthesized by pretreatment process of ball mill method and solution phase route, using [Ni1/3Co1/3Mn1/3]3O4 and lithium hydroxide as raw materials. The physical and electrochemical behaviors of Li[Ni1/3Mn1/3Co1/3]O2 were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, field emission scanning electron microscopy （FESEM） and electrochemical charge/discharge cycling tests. The results show that the difference in pretreatment process results in the difference in compound Li[Ni1/3Co1/3Mn1/3]O2 structure, morphology and the electrochemical characteristics. The Li[Ni1/3Mn1/3Co1/3]O2 prepared by solution phase route maintains the uniform spherical morphology of the [Ni1/3Co1/3Mn1/3]3O4, and it exhibits a higher capacity retention and better rate capability than that prepared by ball mill method. The initial discharge capacity of this sample reaches 178 mA-h/g and the capacity retention after 50 cycles is 98.7% at a current density of 20 mA/g. Moreover, it delivers high discharge capacity of 135 mA-h/g at a current density of 1 000 mA/g.
基金Projects(15B054,17C0400) supported by the Scientific Research Fund of Hunan Provincial Education Department,ChinaProjects(2017JJ2060,2015JJ2042) supported by the Natural Science Foundation of Hunan Province,ChinaProject(2014-207) supported by the Aid Program for Science and Technology Innovative Research Team in Higher Educational Instituions of Hunan Province,China
文摘Different LiNi0.8Co0.15Al0.05O2 cathode materials were washed by ethanol solvent. Inductively coupled plasma atomic emission spectroscopy（ICP-AES）, Fourier transformed infrared（FTIR） spectrum, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, charge-discharge test and electrochemical impedance spectroscopy（EIS） were used to evaluate the elemental contents, structures, morphologies and electrochemical properties of samples. The results show that ethanol washing can remove effectively the synthetic residues LiOH/Li2 O on the freshly-prepared LiNi0.8Co0.15Al0.05O2 and make the sample much more resistant to H2O and CO2, without destroying its bulk structure, surface morphology and electrochemical performances. Moreover, the discharge specific capacity and cycle performance of LiNi0.8Co0.15Al0.05O2 after storage in air with a relative humidity of 80% for three months are improved by immediate ethanol washing.
